Because evaluation of most computerized decision support has been focused on whether the technology works, we still know little about why these systems succeed or fail. For instance, despite computerized reminders for hypertension management in one of the nation?s largest healthcare systems, 22% of hypertensive patients in that system have not met basic blood pressure goals. This project proposes to study a new technology called the Integrated Medication Manager. This application was developed using well-established theories of cognition, notably Hollnagel?s Contextual Control Theory. It is designed to facilitate improved decision-making by helping clinicians to consider more relevant data and to better plan patient care. One of the major features of this system is the explicit linking of patient problems, therapies, and goals. This project will compare the new Integrated Medication Manager to the current version of the Veterans Administration?s Computerized Patient Record System (CPRS). Specific aims are: Aim 1. Identify cognitive components of providers? therapeutic decision making in the field.. Aim 2. Refine and evaluate the Integrated Medication Manager using simulation studies. Aim 1.a. Refine interfaces and logic of the Integrated Medication Manager. Aim 1.b. Compare the performance of the Integrated Medication Manager and usual CPRS. Aim 3. Implement and Evaluate the Integrated Medication Manager in a cluster-randomized trial. Aim 3.a. Assess differences in surrogate clinical endpoints such as blood pressure versus usual CPRS. Aim 3.b Evaluate provider satisfaction and adoption.